According to government agencies like the Drug Enforcement Administration (DEA) and the Federal Bureau of Investigation (FBI), messages sent between iPhone users with the iMessage chat service are "impossible" to access because of iMessage's heavy encryption.

CNET managed to get its hands on a DEA document, which describes a criminal investigation from February of this year. The document said that "it is impossible to intercept iMessages between two Apple devices" because of the encryption -- even with a federal court order.

Apple's iMessage chat service works a lot like a text message, but is transmitted through the internet rather than SMS messages by wireless carriers. It's an encrypted chat program that has become wildly successful. Apple CEO Tim Cook said 300 billion iMessages had been exchanged as of fall 2012.

However, the DEA and FBI are having troubles keeping an eye on suspects who use the chat service. For instance, in a case where the DEA drafted a request for a court order to carry out electronic surveillance under Title III of the Federal Wiretap Act, it found that text messages from Verizon Wireless were incomplete because the suspect was an iMessage user.

"There is a growing and dangerous gap between law enforcement's legal authority to conduct electronic surveillance, and its actual ability to conduct such surveillance," said FBI director Robert Mueller. "We must ensure that the laws by which we operate and which provide protection to individual privacy rights keep pace with new threats and new technology."

The FBI is pushing for legislation on the topic, but even if that doesn't go through, government agencies can employ other methods -- such as obtain a warrant allowing them to go into someone's house/office, install keystroke-logging software and record passphrases. They can also send malware to take control of the suspect's device.

One year ago today, it was reported that the U.S. Department of Homeland Security (DHS) and the U.S. Navy had launched a new research initiative to explore ways of allowing the government to hack into gaming consoles like the Xbox 360, Wii, or PlayStation 3 to obtain information on gamers.